Docker

{
  "name": "miraiclip-render-worker",
  "private": true,
  "type": "module",
  "dependencies": {
    "@miraiclip/core": "^0.6.0",
    "@miraiclip/server-export": "^0.5.0"
  }
}

import { createServer } from "node:http";
import { Readable } from "node:stream";
import { createRenderJobHandler } from "@miraiclip/server-export";

const handler = createRenderJobHandler({
  token: process.env.RENDER_TOKEN, // checked against "Authorization: Bearer <token>"
  browser: {
    swiftshader: !process.env.GPU, // software WebGL, unless the machine has a GPU
    args: ["--disable-dev-shm-usage"], // containers often have a tiny /dev/shm
  },
});

const port = Number(process.env.PORT ?? 8080);
createServer(async (req, res) => {
  if (req.method === "GET" && req.url === "/healthz") return void res.end("ok");
  const request = new Request(`http://localhost${req.url}`, {
    method: req.method,
    headers: req.headers,
    body: req.method === "POST" ? Readable.toWeb(req) : undefined,
    duplex: "half",
  });
  const response = await handler(request);
  res.writeHead(response.status, Object.fromEntries(response.headers));
  res.end(Buffer.from(await response.arrayBuffer()));
}).listen(port, () => console.log(`render worker on :${port}`));

process.on("SIGTERM", async () => {
  await handler.close();
  process.exit(0);
});

FROM node:22-bookworm-slim
RUN apt-get update \
 && apt-get install -y --no-install-recommends wget ca-certificates gnupg fonts-noto fonts-noto-color-emoji \
 && wget -q -O /tmp/chrome.deb https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb \
 && apt-get install -y --no-install-recommends /tmp/chrome.deb \
 && rm -rf /tmp/chrome.deb /var/lib/apt/lists/*
WORKDIR /app
COPY package.json server.mjs ./
RUN npm install --omit=dev
ENV PORT=8080
EXPOSE 8080
CMD ["node", "server.mjs"]

docker build --platform linux/amd64 -t miraiclip-render-worker .

docker run --rm -p 8080:8080 \
  -e RENDER_TOKEN=change-me \
  --cpus 2 --memory 4g \
  miraiclip-render-worker

curl http://localhost:8080/healthz
# ok

import { readFile, writeFile } from "node:fs/promises";

const doc = JSON.parse(await readFile("project.json", "utf8"));

const res = await fetch("http://localhost:8080/", {
  method: "POST",
  headers: { "content-type": "application/json", authorization: `Bearer ${process.env.RENDER_TOKEN}` },
  body: JSON.stringify({
    id: "final", // letters, digits, ".", "_" and "-"
    kind: "video",
    doc,
    options: { format: "mp4", quality: "high" },
  }),
});
if (!res.ok) throw new Error(`render failed (${res.status}): ${await res.text()}`);
await writeFile("final.mp4", Buffer.from(await res.arrayBuffer()));

services:
  worker:
    build: .
    platform: linux/amd64
    environment:
      RENDER_TOKEN: change-me
    ports:
      - "8081-8084:8080"
    deploy:
      replicas: 4
      resources:
        limits: { cpus: "2", memory: 4g }

docker compose up --build

import { readFile } from "node:fs/promises";
import { httpRunner, renderDistributed } from "@miraiclip/server-export";

const doc = JSON.parse(await readFile("project.json", "utf8"));

const runner = httpRunner({
  endpoints: ["http://localhost:8081", "http://localhost:8082", "http://localhost:8083", "http://localhost:8084"],
  headers: { authorization: `Bearer ${process.env.RENDER_TOKEN}` },
  concurrency: 4, // one job per worker: a worker renders one job at a time
});

await renderDistributed(doc, {
  format: "mp4",
  out: "final.mp4",
  runner,
  onProgress: (p) => console.log(p.phase, p.jobsDone, "/", p.jobsTotal),
});